Description

JelleZijlstra

opened on May 19, 2023

Issue body actions

Example:

>>> class B: pass
... 
>>> class X[T]([(x := 3) for _ in range(2)] and B): print(x)
... 
3

This is because a walrus in a comprehension assigns to the immediately enclosing scope, which is now the type parameter scope. I don't think this causes any concrete problem right now, but I don't like it because I'd like to preserve the invariant that type parameters are the only names that can be defined in PEP 695 scopes.

Linked PRs

• gh-104640: Disallow walrus in comprehension within type scopes #104641

Activity

1. JelleZijlstra

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on May 19, 2023
2. JelleZijlstra

   self-assigned this

   on May 19, 2023
3. JelleZijlstra

   added a commit that references this issue on May 19, 2023

   pythongh-104640: Disallow walrus in comprehension within type scopes

   d43cf9c
4. JelleZijlstra

   closed this as completedin #104641on May 19, 2023
5. JelleZijlstra

   added a commit that references this issue on May 19, 2023

   gh-104640: Disallow walrus in comprehension within type scopes (#104641)

   8a8853a
6. carljm

   added a commit that references this issue on May 20, 2023

   Merge branch 'main' into gsallam/main

   ea5965a

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